Mycelium-based materials have seen a surge in popularity in the manufacturing industry in recent years. This study aims to build a lab-scale experimental facility to investigate mycelium growth under a well-controlled temperature and humidity environment and explore how substrates of very different chemical and mechanical properties can affect the microscopic morphology of the mycelium fibers during growth. Here, we design and build a customized green tent with good thermal and humidity insulation for controlling the temperature and humidity and monitor the environmental data with an Arduino chip. We develop our procedure to grow mycelium from spores to fibrous networks. It is shown that a hydrogel substrate with soluble nutrition is more favorite for mycelium growth than a hardwood board and leads to higher growing speed. We take many microscopic images of the mycelium fibers on the hardwood board and the hydrogel substrate and found no significant difference in diameter (∼3 μm). This research provides a foundation to explore the mechanism of mycelium growth and explore the environmentally friendly and time-efficient method of its growth.